Promptly and conscientiously
I have one entry tourist visa for Vietnam. Do I need to show proof of exit date with my itinerary.
Do you mean you have a visa approval letter or a visa already stamped onto your passport?
In case you have a visa approval letter, you only need to present the letter, your original passport, entry and exit form (glued with your photo and stamping fee to get visa stamped onto your passport upon your arrival at Vietnam airport. No proof of exit date and itinerary are required.
In case you have visa already stamped before your travel to Vietnam, you only need to present your passport with visa and the entry and exit form upon arrival in Vietnam.
I hope this information is clear to you.